This document shows two ways to measure current with an analog input for voltage.
Example:
Resistance: 0.1 Ohm
Load Capacity: 10 W
Measured Voltage: 0.5 V
R = U / I
I = U / R
I = 0.5 V / 0.1 Ohm
I = 5 A
Maximum current for Load Capacity 10 W:
P = I² * R
I = sqrt (P / R)
Imax = sqrt (10 W / 0.1 Ohm)
Imax = 10 A
LabVIEW Code:
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There are different Hall-Effect-Based Current ICs. This example shows a ACS712 from Allegro MicroSystems, Inc.
You can order the IC with breakout module or you can build your own board. In ACS712 datasheet is a circuit diagram. Search in web for ACS712 datasheet. AC712 deliver not the best results if you want to measure only some milliampere.
ACS712 consists of a linear Hall circuit with a copper conduction path located near the surface of the die. Applied current flowing through this copper conduction path generates a magnetic field which the Hall IC converts into a proportional voltage.
This picture shows the ACS712ELCTR-20A-T with breakout module. ACS712ELCTR-20A-T has an optimized Range of +/- 20 A and a sensitivity of 100 mV/A.
Please note that there are different Hall-Effect-Based Current ICs with different ranges and sensitivities.
The LabVIEW code for the Hall-Effect-Based Current measurement is the same like for Shunt Resistor.
The scaling depends on the Hall-Effect Sensor type.
Hi Everyone!
I am using Ni cRio and 9201 module, and want to measure current using Allegro ACS 750. But unable to measure the same using LabView. Kindly help me building VI in Labview.